1. Field of the Invention
The present invention is directed to a method of monitoring the operating condition of a machine.
2. Background of the Invention
Monitoring the state of machinery, also termed condition monitoring, relates to the detection of changes in the condition of a machine to be monitored in order that critical operating states of the machine in particular are detected promptly and, for example, to prevent damage to the machine. Methods of machine condition monitoring are already known from practice. In methods known from practice, at least one machine parameter is monitored during operation of the machine to be monitored, namely in such a way that a change in the machine condition, particularly a critical operating state of the machine, is deduced when at least one monitored machine parameter reaches a limit value. In so doing, it is possible, for example, to compare machine parameters such as, e.g., an electric current, an electric voltage, a temperature, a pressure, or also vibrations in the machine to be monitored with a global limit value which is applicable to the entire operating range of the machine. For example, it is known to determine a cumulative vibration value based on a vibration analysis carried out over the entire operating range of the machine and to compare this cumulative vibration value with a global limit value which is valid for the entire operating range, and a change in the machine condition is deduced when the cumulative vibration value reaches the global limit value. But while machine condition monitoring can be implemented by such known methods, their diagnostic power is limited.
On this basis, it is an object of the present invention to provide a novel method of machine condition monitoring. According to the present invention, at least one monitored machine parameter is monitored depending on at least one other machine parameter within defined operating point ranges, and a change in condition is deduced when at least one monitored machine parameter within a defined operating point range reaches at least one limit value individual to the operating point range.